Tight hamstrings are a common culprit of lower back pain and frequently contribute to back injuries in athletes.
The hamstrings are a finicky group of three muscles located on the backs of our thighs. When these muscles lose their elasticity they tend to lock the pelvis, removing the normal curve of the lumbar spine and flattening the lower back. This rigidity makes your back work extra hard to accomplish even simple tasks like bending down to pick something up, let alone the workouts and training that athletes put their bodies through on a daily basis. Without proper attention to caring for tight hamstrings you are bound to end up achy, or worse, injured.
To keep the hammies healthy, I have my athletes take this hamstring stretch on their backs with a strap. After holding for 10 breaths, open out to the left and right sides as well.